1. Field of the Invention
This invention relates to dental implants and drills for forming sockets for receiving the anchor section of such dental implants.
2. Background Information
Dental implants have been employed for generations to replace lost and damaged teeth. In general, most modern dental implants consist of a fixture that is screwed or press-fit into a socket that has been drilled or carved into the patient's jawbone. The size of the fixture varies in accordance with the location and anatomy of the mouth. The fixture is held in place by friction or adhesive. Many modern implant fixtures include a surface having a generalized texture and/or ridged surface. This allows for eventual osseointegration—that is, the patient's bone grows into and around the fixture to more permanently secure it to the jawbone.
The fixture may include a cylindrical or conical abutment that projects upwardly from the socket to provide a mounting point for an artificial crown or bridge. Such an abutment may be integral with the fixture, or more commonly, is separately attached to the implant fixture using fasteners, such as screws. The implant fixture may have a polygonal socket with a threaded bottom that ensures proper rotational orientation for the inserted abutment and, hence, proper orientation for the crown or bridge that is seated on the abutment. The crown or bridge simulates the actual tooth or teeth being replaced. The crown or bridge can be attached to the abutment by a variety of techniques including adhesives.
A common disadvantage of current implants is that the socket formed in the fixture is either too small in diameter (in the case of a drilled and threaded fixture) or too large in diameter (in many press-fit fixtures). In general, natural tooth sockets in the jawbone tend to be ovular, and a round hole either underfills or overfills this area. Thus, where the diameter is too small, the fixture may not fully fill the original tooth socket and/or may not be firmly attached. Conversely, the circular hole that must be drilled in the jawbone (in the tooth socket) to accommodate a larger, round cross-section fixture may cause the walls of the jawbone to be overly thinned in places, leading to possible failure of the bone. U.S. Pat. No. 5,785,525, entitled DENTAL IMPLANT SYSTEM, by Weissman contemplates the formation of implants having a non-round cross section. A non-circular shape better conforms to the actual shape of a socket of the tooth. However, forming a non-circular hole having a depth and size that accurately reflects the volume and desired of the implant is quite difficult. In general, non-circular holes are formed using a broaching technique, in which a linear drill is driven using hammer blows into the jawbone. The possibility of overdrilling and/or fracture is always present in this technique. In addition, Weissman creates straight non-circular holes without a varying cross section along their lengths. A natural socket is tapered inwardly from the gumline to the root. By removing a large quantity of material near the root, the risk of infection and weakening of the jawbone is increased.
It is, thus, desirable to provide a system and method for forming a receiving socket for a dental implant that avoids the disadvantages of the prior art. A drill that more easily and accurately creates such a socket is desirable and the implant fixture received by the socket should more naturally conform to the contours of the original tooth socket. Also, it is desirable to provide a system that allows for immediate replacement of the tooth following tooth extraction.